By Christina Cheddar Berk, CNBC.com
Trendiest Halloween Costumes
Each Halloween there are many classic themes people use to inspire their costume choice, but every year there are some that stand out from the rest.
This year Halloween spending is projected to rise 9 percent to $6.86 billion, according to a survey conducted by BIGResearch on behalf of the National Retail Federation trade group. There are two reasons for the increase: More Americans are celebrating the holiday, and more American adults are dressing up in costumes as part of the fun. Based on the survey, it is expected Americans will spend $1 billion on costumes this year.
See the Slideshow: Trendiest Halloween Costumes for Adults
As consumers put more focus on finding the right costume, there has been a trend to "mash up" or create unique costumes by blending elements from several existing costumes.
For those who are either too time-pressed or not as creative to create their own costumes, don't worry. There are plenty of costume manufacturers putting fresh twists on old themes. They find just the right elements to be recognizable, while freshening up the concept to make it look like something never seen before.
Pirates of all kinds are very popular right now among all age groups. This pirate costume, manufactured by Roma, is a perfect example of how the right elements-boots, swords, and hats-can be used to establish the theme, but the style of the costume and the material it's made of provide a unique twist.
Although pirates are a very traditional Halloween theme, they have become more popular in the wake of moves such as Walt Disney's "Pirates of the Caribbean."
Retail $14.99 and up
Do you have one speed, one gear, go? Perhaps you can dress up like a "total bitchin' rock star from Mars" this Halloween. You'll have company.
Major media events often provide inspiration for Halloween, and Charlie Sheen's meltdown was particularly spectacular.
There are plenty of ways people will be putting together Sheen characters. Some will interpret Sheen's catch phrases, while others will mimic him. To help pull the costume together, there are masks and wigs, even bowling shirts, Fedora hats, sunglasses and shirts that say "Winning." Adding a "Goddess" on each arm can't hurt either, but I'm afraid the Tiger Blood is sold separately.
Pictured: Prince William and Kate Middleton costumes
Let's face it: We don't always have a royal wedding to gawk at. So it should come as no surprise there are costumes that will have you looking like the royal couple, Prince William and Kate Middleton, on their big day.
The outrageous hats of wedding guests Princess Beatrice and Princess Eugenie also may inspire some do-it-yourself costumes this year.
Alice in Wonderland
Pictured: Mad Hatter
Tim Burton's movies continue to inspire many Halloween looks. Since the debut of his version of "Alice in Wonderland" last year, the Alice theme has been popular not only for Halloween, but also during the year as a theme for parties.
There are many different versions of the Alice, Mad Hatter, and Queen of Hearts costumes sold by different manufacturers. Pictured is one with a sexy vibe, manufactured by Roma.
Pictured: Katy Perry "California Gurl" costume
After making headlines with her meat costume, Lady Gaga became one of the hottest themes for Halloween costumes last year. No doubt there will be plenty of "little monsters" out and about this year dressed in both homemade Lady Gaga apparel, as well as in store-bought versions. Even domestic doyenne Martha Stewart appears to be channeling Gaga on thecover of her Halloween issue this year.
One of the more popular takes on the Lady Gaga theme this year could be the Jo Calderone outfit that she wore to MTV's Video Music Award Show. Don a greaser wig, a white T-shirt, and a leather jacket, and you're almost there.
Still, there will likely be some competition this year from singer Katy Perry. There are two main costumes that stores will be selling that were inspired by Perry's "California Gurls" video.
Retail: $39.99 each
Without a doubt, one of the best-selling costumes this Halloween for both children and adults are the ones based on the characters in the Angry Birds game, according to Halloween costume retailers.
According to Halloween Express spokesman Brad Butler, manufacturers were scrambling to get the Angry Birds costumes to retailers in time for Halloween. Judging by sales, it looks like it was worth the effort.
"There is a lot of interest in the funnier stuff," Butler said. "In particular, the Angry Bird costumes. It caught us by surprise."
There are Angry Bird costumes for all age groups, but adults can pick from either a costume that covers their body, or a mask that covers their head.
Get inspired, see the full list of the Trendiest Adult Halloween Costumes
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By Christina Cheddar Berk, CNBC.com